Kitchen Ventilation

Worldlywanderer

We are in the process of designing a new interior for our kitchen. Luckily, we do not require a building warrant so this question is about effective ventilation rather than satisfying catch-all regulations. The room is split into two distinct areas with a 2.4m high opening between them; One area, for dining is L 5.0, W 2.6, H 2.6 with double doors into the garden.

The second area is where the work is done and is L 4.5, W 3.3, H 2.9. The main oven is located in the utility room so all cooking will be by a combination of induction hob, halogen oven and combination microwave. There are double casement windows at one end and a top hung casement at the other.

In view of the significantly lower levels of moisture produced by these modern cooking methods and there being only two of us living in the house I feel the level of extraction suggested by building regulations is excessive. We do not intend fitting a cooker hood but i feel that a wall mounted 60 lps extraction fan fitted near the ceiling with a manual boost and a humidity detector would be adequate.

I'd be grateful for views from anyone with experience.

thescouselander

I'm not sure what "modern cooking methods" are but there are going to be occasions when ventilation is needed.

Good ventilation will stop that horrible sticky stuff forming on the top of the units and generally preserve the kitchen in better condition.

Any reason why you don't want a cooker hood?

cyclonebri1

You really do need a cooker hood to be honest and not to comply with building regs either.

Does't matter how you heat it, anythin g boiling away on any type of hob will create both smell and moisture and removing them at source is by far the best way.

Even cooking in a closed oven will create great the same issues.

If it's the routing of ducting thats the issue then there are ways around most situations.

On no account would I suggest a recirculating hood, and the wall mounted fan would need to be a decent dia to have the desired effect.
With an open area like you have eating your dinner with the smell of boiled cabbage seeping in from the prep area is the risk.

In conclusion I'd say you need a good reason not to fit a cooker hood, but you haven't mentioned why??

System

my kitchen didn't have any extraction to it at all - and there was no scope for a cooker hood.
Ended up getting a 150mm extract on a humidistat and it really makes a huge difference to the smells/moisture in the kitchen when cooking.
Presumably you will still be cooking on the hob, there's no real way to avoid moisture when you're boiling a pan of water even with a modern induction hob!

Worldlywanderer

Thanks to the _r_sole for a spot on response. Clearly, you are correct that moisture will be produced in any form of cooking but modern methods have considerably reduced this. One example is the notorious noxious odour of boiled cabbage. In the bad old days when we boiled vegetables for hours the sulphur smell produced by cabbage was a serious problem. Now that we boil faster and shorter or even steam instead and understand that aluminium pots don't mix with cabbage the odour has been virtually eliminated. Similarly, when breakfast was a fry-up every day the fat and moisture produced in cooking was horrific by current standards. You should try producing fifty or so Scottish breakfast at a sitting to discover the truth of this.

The healthier meals and more efficient methods enabled by induction hobs, combination microwaves and halogen ovens all contribute to a reduction of odours and moisture. I do agree with cyclonebri1 that recirculating hoods are a waste of money - they exist to add to salesmen's commission and contribute little to the enhancement of the kitchen environment. Cooker hoods in general are part of the fast disappearing fitted kitchen mania so loved by Magnet, B&Q and Homebase to mention but a few of the design deserts which populate our High Streets. Since we will have no fitted units whatsoever in our kitchen the ubiquitous cooker hood will also be consigned to the dustbin of culinary history.

What we are trying to do is apply a little used skill possessed in a least some quantity by all of us - common sense. As Cyclonebri1 wrote - the best way to eliminate odours and moisture is at source. Reducing the amount of fatty foods cooked, applying modern standards to cooking - a 900 watt combination microwave will produce a beautiful moist and light sponge pudding or a loaf of Irish soda bread in twelve minutes where the former would take 45 and the later 60 minutes in a 2.7 kW convection oven. Induction hobs heat the food not the atmosphere around a hob, they require no warm-up time and combined with well designed cookware produce dishes faster with less use of energy.

I think I've answered all of thescouselander's points but would add that the issue here is not my disagreement on the need for ventilation but what, in practical terms, works. Having lived in a small flat with an internal kitchen and wall units between the traditional gas cooker and extract fan I can identify completely with thescouslanders concerns. More recently, having lived with kitchen units and a recirculating fan whose filter had not been changed in years I also empathise with the other two correspondents but for a practical response I must thank the_r_sole. Humidistats and boosters on through wall extractors seem to me the way to go so it is helpful to hear from someone with practical experience of this method.

thescouselander

Well if you do want to use a fan I'd have thought a larger one would be better. By comparison a good domestic cooker hood might be shifting 140 L/s.

The type of fan also makes a difference as the wall mounted variety tend to use axial fans which don't produce much pressure where as a centrifugal fan will be much better at pumping air down long runs of pipe and drawing new air into the room. Usually cooker hoods use centrifugal fans which gives them a good pumping capacity. I've never found wall mounted fans to be that effective although I've only ever used them in the bathroom.

Worldlywanderer

Thank you thescouselander; as you say I have completely rejected the idea of a cooker hood. Your point about centrifugal fans is interesting as I have been considering these - they are available in both wall mounted and inline models.

It may be worth making the point that a kitchen with two windows on opposite sides inclines the user to open them when the weather is clement making the need to mechanical access redundant, to all intents and purposes, for around six months of the year.

Smiley_Dan

Part F is a bit of a joke really. We're very behind on ventilation; the standard response appears to be "knock a few holes in the wall".

Some of this depends on the context. How air tight is the rest of the house? If you have a proper whole house ventilation method it is perfectly acceptable to use a recirculating hood. Smells will take longer to disappear than with a high powered external fan, but it's about balancing priorities. When that fan isn't working, it's still leaking heat.

bildersfriend

I would seriously rethink, the most efficient method to control condensation is extraction hood.

Worldlywanderer

Missed who suggested a recirculation fan as a method of controlling condensation but quite agree with bildersfriiend that it isn't likely to work. Agree also with Smiley Dan on Part F but luckily Scotland is different. Also agree that conext is everything. We have a Victorian sandstone villa but our EPC rating of B83 shows how effectively it is insulated. That said it is hardly cost effective to take the MVHR route for our needs an a single hole in the wall, while not PC is likely to provide the only economic extract. What we need to do is decided just which fan will do the job properly.

I'm taken , after some research by the idea of a centrifugal fan which would allow us to hide the works in the ceiling and extract through the wall in the area between ground and first floors.

Smiley_Dan

I don't think anyone did suggest using a recirculation hood to control condensation, to do so would be nuts!

What I'm not sure about is the combination of recirculating hood plus single room HRV (SRHRV).